Analysis Of Cutting Forces Research Articles

An experimental study of ultrasonic-knife cutting for a woven carbon fiber preform by an industrial robot

This study investigates the effect of the cutting process parameters on the cutting forces and the quality parameters of a woven carbon fiber preform during robotic ultrasonic-knife cutting. An ultrasonic cutting device, with a power of 1200 W, a frequency of 24 kHz, and an amplitude of 60 µm, mounted on the end effector of a six-axis degree of freedom industrial robot to make linear cuts. A three-level factorial experimental design was used to examine the effect of the feed rate (1 m/min to 5 m/min) and the knife’s attack angle (45° to 75°) on the cutting forces, the dimensional accuracy of the machined preform coupons, and the damage on the machined preform edges. The cutting force analysis results show that the increasing feed rate resulted in increasing feed force and thrust force. However, the increase of the attack angle increases the feed force but decreases the thrust force. The average width and damage of the ultrasonic knife cut preform coupons are highly related to the process conditions. The combination of the low feed rate, 1 m/min, and the low attack angle, 45°, resulted in dimensional errors ranging from 253 μm to 365 μm oversized from the programmed 15.0 mm width with no damage. When the feed became 3 m/min and 5 m/min at the attack angle of 75°, the preform coupons’ dimensional accuracy and damage formation worsened. In these conditions, the ultrasonic knife attached to the industrial robot arm could not cut the preform plate effectively, so the tows on the preform were unevenly cut or dislodged.

FEM-supported machine learning for residual stress and cutting force analysis in micro end milling of aluminum alloys

FEM-supported machine learning for residual stress and cutting force analysis in micro end milling of aluminum alloys

Modeling and analysis of radial throw of micro-milling tool based on tool-attachment errors in high-speed rotating

In the process of micro-milling complex structures, radial throw is likely to cause lower dimensional/form accuracy, which will severely affect the performance of the components. Therefore, it is necessary to investigate the source contributing to the radial throw. According to the kinematic process of the radial throw arising from the attachment errors of the micro milling cutters, a mathematical model considered the attachment errors and the variable section geometry of the micro milling cutters was established to predict the radial throw on the basis of the principle of minimum total potential energy and the Timoshenko beam theory. In comparison to the mathematical model, the proposed finite element model (FEM) presetting the attachment errors shows the effect of modal vibration and the variation of radial throw with attachment errors. To further investigate the environmental factors influencing the radial throw, a measurement method based on the laser measurement system is presented to achieve the on-machine measurement of runout, and a specific extraction method of attachment errors was proposed to help validate the mathematical model. The difference between the results of the mathematical model, FEM, and the experiment is not exceeding 10 % within 3 μm of the maximum runout. Radial throw varies strongly with attachment errors, and the high rotation speed will aggravate the system instability caused by the attachment errors. The main contributor among experimental factors to the variation of runout is the form accuracy of micro milling cutters, accounting for 4.7 % at the highest. This method can provide a theoretical basis for the sources of unbalanced cutting force analysis and the improvement of dimensional/form accuracy.

A Novel Approach for Dry Cutting Inconel 718 in a More Sustainable and Low-Cost Way by Actively and Purposely Utilizing the Built-Up Layer.

Due to its physical and mechanical properties, Inconel 718 remains a difficult-to-cut material and there is an urgent need to develop a more sustainable and low-cost way to machine it. A novel approach for dry cutting Inconel 718 by actively and purposely utilizing the built-up layer (BUL), which can be called the self-protective tool (SPT) method, is proposed and investigated in detail in this paper. Various cutting experiments were carried out using the age-treated Inconel 718 and uncoated cemented carbide tools. The formation condition of the BUL, its formation mechanism, its stability, and its protective effect were examined by measuring the tools after cutting using a scanning electron microscope (SEM) and laser confocal microscopy (LCM). The influences of BUL on the cutting process were investigated using cutting force analysis and surface roughness analysis. The results confirmed that the stability of the BUL is very high, and the BUL can not only significantly protect the tool from wear but also reduce friction at the tool-chip interface and maintain surface roughness. It also revealed that the height of the BUL can play a very important role in its protective effect. Comparative experiments verified the effectiveness and generalizability of the proposed SPT method.

Wear behavior of innovative niobium carbide cutting tools in ultrasonic-assisted finishing milling

The resources of niobium exceed the ones of tungsten by an order of magnitude. With 92%, Brazil is today the main global producer of niobium. Hence, niobium carbides (NbC) are a sustainable and economic alternative to conventionally used cutting materials, especially tungsten carbides (WC). Moreover, NbC can be used in Ni alloy matrix and thus offer significant advantages by substituting WC in Co matrix as cutting materials in terms of health risks and raw material price and supply risk. Based on recent studies which found an increased performance of NbC compared to WC cutting tools in machining higher strength steels, the composition NbC12Ni4Mo4VC was chosen for finish machining of a high-strength steel S960QL in this study. The experiments were carried out on an ultrasonic-assisted 5-axis milling machine using NbC tools specially made to benchmark them with commercially available coated WC cutting inserts. In addition, the influence of a coating system for the NbC inserts is tested and evaluated for its performance in the cutting process. Tool wear and cutting force analyses are implied to identify optimal parameter combinations as well as tool properties for the novel NbC tool. Together with the oscillation of ultrasonic-assisted milling, the loads on the component surface and the tool can be reduced and the wear behavior of the novel NbC tool can be refined. These milling tests are accompanied by standardized wear tests, i.e., pin-on-disc, between the aforementioned material combinations, and the results are correlated with each other. Finally, the behavior when using hard-to-cut materials such as Ni alloys, or innovative materials such as iron aluminide is also being tested, as these are constantly in the focus of machining optimization. With this strategy, comprehensive knowledge is achievable for future efficient application of NbC for milling tools, which have already been researched for decades using WC.

Study on helical hole-making process of CFRP/Al alloy laminated materials

To ensure assembly accuracy and efficiency, the holes are made directly on the laminated material composed of CFRP and Al alloys. However, due to the sudden change of axial force in the transition area with different laminated sequence, a method of micro-lifting tool was proposed. First, the motion of helical milling was analyzed. The level values of influence the quality of the hole-making are determined, such as spindle speed, pitch, and preload. The response surface method (RSM) was used to design experiments, and the burr height between Al alloy interlayer and the tear value of CFRP was used as the standard to analyze the experimental results. The optimal parameter combination for different laminated sequences were predicted and used for cutting force analysis. The results show that sudden increase in cutting force is prone to occur in the transition area. Secondly, the hole-making processes with variable parameters study were carried out, and the method of micro-lifting tool is proposed for the experimental study of the sudden change of axial force in the transition between interlayer with constant parameters. The results show that the aperture of the hole-making with variable parameters of the laminated materials using the optimal process parameters all meets the H9. The interlayer burr of the Al alloy and the tear value of the CFRP at the entrance and exit conform to the technical requirements. The hole-making axial forces of CFRP and Al alloy are less than 50 N and 60 N, which are 70% and 83% of constant parameters milling.

A decision tree-assisted polynomial regression model with application in the cutting force analysis of cutters of a tunnel boring machine

Polynomial regression (PR) has been widely used to model simulations and experimental engineering data. The regression relationship of engineering data often varies greatly in different sub-sample spaces, making it difficult to evaluate accurately using a unified PR model. To solve this issue, a decision tree-assisted polynomial regression (DTPR) model is proposed in this article, in which a new decision tree is designed to partition the sample space according to the regression relationship. To make a prediction for a new sample, it is first compared from the root node of the decision tree until it reaches a leaf node; then, the output is obtained through the PR model of the leaf node. The experimental results indicate that the proposed model can show competitive performance in both mathematical functions and engineering cases. The proposed model is applied to the cutting force analysis of cutters of a tunnel boring machine to demonstrate its advantages.

Influence of post processing on the micro-machinability of selective laser melted AlSi10Mg: an experimental investigation

ABSTRACT In the present era, machinability studies of selective laser melted (SLM) samples are immensely significant due to the rapid development in hybrid additive manufacturing. In such hybrid process material removal is also performed along with the 3D fabrication of near-net shaped products. Therefore, this work is an effort to compare the machinability characteristics of various samples, namely, cast and SLM produced AlSi10 Mg along with their effect when subjected to T6 solution heat treatment. In the cutting force analysis, it is found that there is an increase in the thrust force (114.8%) and cutting force (33.25%) for SLM manufactured samples in comparison with cast samples. On the other hand, heat treatment on the SLM fabricated samples resulted in the decrease of thrust force (6.94%) and cutting force (13.29%). In addition, the heat treated SLM produced sample showed a steep reduction in Sa by 86.5% compared to as-printed sample. Moreover, lengthier chips were observed in both cast and SLM fabricated specimens, whereas shorter and curlier chips were observed in both heat treated specimen.

Geometric definition, rapid prototyping, and cutting force analysis of cylindrical milling tools with arbitrary helix angle variations

In this work, a method is developed for geometric definition and analysis of cylindrical milling tools having various free-form variations of helix angle. The method is based on replicating a position vector on each cutting edge to generate a point set for the whole tool envelope using piece-wise rotation and magnification matrices which are varied according to mathematical laws describing the intended variable shape of the tool. The computed point sets are applied in additive manufacturing of samples of such tools having non-conventional shape features by transforming the point sets to stereolithography formats that are sliced to guide the 3D-printing processes. This manufacturing route that simplifies the realization of arbitrary helix profiles on milling tools is a major contribution of this work since such tools are gaining popularity for their passive damping of vibrations and reduction of cutting forces but are notoriously difficult to manufacture, limiting their exploitation. Analyses are shown about the effects of the considered variable profiles on milling cutting force. These suggest that cutting forces can be greatly suppressed by the proposed free-form helix angle variations. For example, relative to a conventional fixed helix tool of same mean helix angle, the innovative tools recorded 40.33%–84.42% and 60.53%–67.81% force reductions at axial depths of cut of 1 and 5 mm. This demonstrates that innovative variable tool profiles which can be realized through the simplified rapid prototyping technique are promising for advanced sustainable manufacturing of parts with preferred surface conditions.

Application of vibration singularity analysis, stochastic tool wear, and GPR-MOPSO hybrid algorithm to monitor and optimise power consumption in high-speed milling

Power consumption in manufacturing direct affects production costs and the environment. Therefore, the process of evaluating and researching power consumption in the machining process is very important. During high-speed milling, the power consumption varie`s due to tool wear and radial deviation. Therefore, a new model power consumption optimization is proposed based on cutting mode factors taking into account tool wear and radial deviation. In the existing power consumption models, studies on the effects of radial deviation and tool wear have not been thoroughly investigated. Stochastic tool wears established during high-speed milling is established in combination with the cutting force analysis model and wavelet singularity vibration point analysis. The nonlinear processes due to stochastic tool wear and cutting edge geometry were considered in the model. To optimize power consumption and establish a model for the real-time prediction of power consumption, a new GPR–MOPSO hybrid algorithm was developed based on Gaussian process regression (GPR) and multi-objective particle swarm optimizations (MOPSO). In order to verify the feasibility proposed monitoring and optimization model, experimental processes high-speed milling have been established. Results showed that the presented improvement model will reduce power consumption by 20.38% compared with manufacturer manuals chosen process parameters.

DEPTHS OF CUT IDENTIFICATION IN 3-AXIS MILLING USING CUTTING FORCE SPECTRUM

Cutting forces analysis is one of the most important means of improving machining quality and productivity. In 3-axis milling, the frequency domain analysis of the cutting forces provides information which can be adopted for both predicting and monitoring the cutting process. However, the evaluation of the cutting forces spectra requires the application of specific tools (i.e., Fourier’s Transform) to the time domain representation of the same cutting forces. This paper presents analytical formulations to directly evaluate the cutting force spectra starting from the tool geometry and the cutting parameters. The proposed formulations start from the expression of the cutting forces as a Fourier series and enhance the predictions showed in previous works by reducing the overall number of calculations needed. Then, the proposed formulations are applied to identify both radial and axial depths of cut exploiting the normalized cutting force spectrum. Finally, the proposed formulations and their application were numerically and experimentally validated. This work represents a preliminary step in the development of a monitoring system to identify cutting conditions in 3-axis milling.

Forces Shapes in 3-Axis End-Milling: Classification and Characteristic Equations

In 3-axis milling, cutting force analysis represents one of the main methods to increase the quality and productivity of the process. In this context, cutting force shape gives information of both monitoring and prediction of the cutting process. However, the cutting force shape is not unique, and it changes according to the cutting strategy, tool geometry, and cutting parameters. This paper presents a comprehensive approach to predict and classify cutting force shapes in 3-axis milling operations. In detail, the proposed approach starts by classifying the cutting force shapes for a single fluted endmill (i.e., single flute force shape), and, considering how the single flute force shapes may overlap one another, it extends the classification to a general multiple-fluted endmill. Moreover, the method provides, through analytical equations, angles, and magnitude dimensionless parameters of each key point, describing each shape classified. Finally, the proposed approach was experimentally validated through several milling tests in different cutting conditions.

Cutting force analysis of oak for the development of a cutting force model

ABSTRACT The cutting process of oak (Quercus robur) was investigated by means of a novel testing approach. A unique testing device, enabling nearly linear stand-alone cuts, was used. The specimens climatized to 6 different moisture content levels were machined within cutting velocities ranging from 5 to 80 m·s−1, at 5 cutting fibre angles from along to across the grain, and at different uncut chip thicknesses of up to 0.5 mm. The precise quartz sensor utilized for observing cutting forces enabled insights into the cutting mechanism involved while wood disintegration. Cutting velocity evolved as a key process parameter strongly influencing cutting force. Evaluation of uncut chip thickness showed a regression that was strongly influenced by particular force components. The friction force generated by “ploughing” the surface was relevant when cutting thin chips. In contrast, the part of force introduced by chip formation affected the process weightily in the case of cutting a thick chip. When cutting parallel to the grain lower forces were observed than cutting perpendicular to grain orientation. Obtained data supported the mathematical force prediction model establishment involving several parameters (e.g. cutting velocity, cutting fibre angle, uncut chip thickness, and moisture content).

Identification method for the dynamic cutting force variation of a high energy efficiency milling cutter

The dynamic cutting force of a high energy efficiency milling cutter is an important indicator for evaluating the stability of the cutting energy efficiency. The existing cutting force analysis focuses on the main characteristics and influencing factors of the cutting force variation in the cutting process, ignoring the influence of the variation of the cutting layer parameters with the cutter tooth error in different cutting stages, and the dynamic cutting force variation is uncertain. In this research, the analytical model of the instantaneous cutting volume of a milling cutter was developed in order to obtain the time-frequency characteristics of the instantaneous cutting volume with the cutter tooth error. According to the sudden changes of the cutting force and the milling vibration, the variations were studied in different cutting stages. The dynamic cutting behavior sequences such as the instantaneous cutting volume, milling vibration, and dynamic cutting force were constructed to characterize the mapping relationship between the dynamic cutting behavior of a milling cutter. Based on these approaches, the identification method for the dynamic cutting force variation of a high energy efficiency milling cutter was proposed. The effectiveness of the method was verified by the results of the milling experiment and the dynamic cutting behavior response analysis. The results showed that the proposed method could effectively identify the variation and its control variables for the dynamic cutting force in the cutting process, and the method could provide a scientific basis for constructing the dynamic cutting force model of a high energy efficiency milling cutter.

A Multistage Cutting Tool Fault Diagnosis Algorithm for the Involute form Cutter Using Cutting Force and Vibration Signals Spectrum Imaging and Convolutional Neural Networks

In a machining system, tool condition monitoring systems are required to get a high-quality product and to prevent the downtime of machine tools due to tool failures. For this purpose, tool condition monitoring systems have become very important during the years since the mechanical faults can cause high cost. This study introduces a multistage cutting tool fault diagnosis method to detect the presence and level of the involute form cutter faults on the by the cutting force and vibration signal analysis. Therefore, different fault levels (low, medium and high) were generated on the involute form cutter as a tool breakage. During the experiments, the cutting force, vibration and acoustic signals were gathered with three different feed rates for each fault level. The gathered signals were processed by a multistage signal processing algorithm developed in the MATLAB environment. As an initial step, the continuous wavelet transform of the obtained signals was taken and saved as an image by the developed algorithm. After that, a convolutional neural network model is trained and tested by using the obtained images. The developed algorithm firstly checks the presence of the cutting tool fault. Once the algorithm labels the cutting tool is damaged, it then checks the damage level of the cutting tool fault. It is observed from the results, cutting force analysis is sufficient for the detection of cutting tool fault. On the other hand, the cutting force signal analysis is insufficient to detect the damage level of the cutting tool. Therefore, the vibration signal analysis is required to detect the damage level of the cutting tool. Results prove that, by the vibration analysis, the developed algorithm could detect not only the presence of the damage on the cutting tool but also the damage level. The results of the algorithm for each stage and signal are given in the results section.

Multi-factor influence on the roughness of the finished surface

The aim of this work is to develop a novel approach for ensuring the quality of the finished surface based on a multi-factor model. The proposed model can take into account most of the machining process parameters. The main parameters include cutting conditions, dynamic stability of the cutting process, thermal effects in the cutting area. The development of a multi-factor model was based on a literature review and experimental data obtained from the cutting force analysis and colour pyrometry. The data obtained were summarised into a unified multi-factor model. We analysed the key literature sources and summarised the experimental data and findings to assure finished surface quality when controlling one of the input parameters of the machining process. It was shown that the surface quality (roughness) can be achieved by applying different machining parameters. They include the rational cutting conditions, a change in the geo m-etry of a cutting tool, reducing the relative spacial dynamic vibrations of the tool relative to the working surface of the raw part, using the methods influencing the physical and mechanical properties of the processed materials. It was established that the process dynamic stability, the cutting conditions or the chip formation process can be used as an input parameter. The proposed scheme of multi-factor influence of processing parameters on the output parameter - the surface roughness - applies to any materials under processing. The created model takes into account all input parameters of mechanical processing. It aims at the quality management of the finished surface based on the required performance characteristics of the items. Based on the proposed multi-factor scheme, we plan to create an adaptive system capable of controlling the mechanical processing based on a computer numeric control machining centre.

The effect of fiber orientation on mechanical properties and machinability of GFRP composites by end milling using cutting force analysis

In recent years, glass fiber-reinforced polymer (GFRP) composite materials have become a viable alternative material for different engineering applications due to their superior/excellent properties. The strength of the composite is positively related to the orientation of the fiber material. However, the machinability is still a problem when components are manufactured using the GFRP composites due to their anisotropic properties. The aim of this analytical research paper is to investigate the influence of fiber orientation on the strength and machinability in slot milling of GFRP fabricated using the vacuum infusion method. The fiber orientations of 0°/90° and ±45° are used for the fabrication of GFRP composite laminates. The experiments were conducted using an orthogonal array. Analysis of variance was employed to determine the influence of milling parameters such as cutting speed, transverse feed rate, and axial depth of cut (A.D.O.C.) for the surface finish (Ra), cutting force, and Machinability index (MI). The MI is calculated based on specific cutting pressure. The influence of fiber orientation on the cutting force and surface topography was analyzed. It was concluded that the cutting forces were significantly influenced by the fiber orientation and not affected by the machining parameters. The results revealed that the transverse feed rate was the primary influencing parameter responsible for the increase in MI (40 to 56%). The A.D.O.C. was accountable for the increase in cutting force (55 to 94%). Similarly, the cutting speed influenced Ra, which increased from 17 to 37%.

New mechanistic cutting force model for milling additive manufactured Inconel 718 considering effects of tool wear evolution and actual tool geometry

Abstract Inconel 718 is widely used in aircraft industry due to its properties. Nevertheless, its mechanical and chemical properties make it hard-to-cut. As a consequence, additive manufacturing is developed in order to get near net shape part before machining. Thus, this article presents a study on the machinability of the Inconel 718 obtained by additive manufacturing compare to one from wrought bar. Firstly, the machinability in milling is investigated through microstructure observation and cutting forces analysis, then a tool wear observations for both material are realised. Thereafter, novel formulations of cutting force model in milling are developed associated to precise treatment and identification process. Thus, the cutting forces are modelled with a mechanistic approach fully parameterized, and furthermore the tool geometry as well as the local forces model consider tool flank wear effect. This study shows that additive manufactured Inconel 718 has a better machinability and that considering tool wear with tool geometry evolution improves the model precision.

Study on the protective effect of built-up layer in dry cutting of stainless steel SUS304

This work presents a systematic and comprehensive investigation of the protective effect of built-up layer (BUL) in dry cutting of stainless steel SUS304. A detailed examination of BUL and built-up edge (BUE) formation conditions, their formation mechanisms, and their protective effect was carried out at different cutting speeds (5–140 m/min), and different feed rates (0.02–0.1 mm/rev). The uncoated cemented carbide tool was used as a cutting tool. The dimensions of BUL/BUE and tool wear were measured by scanning electron microscope (SEM) and laser confocal microscopy (LCM). The protective effect of BUL/BUE was characterized using flank wear progression, as well as crater wear progression, cutting force analysis, and surface roughness analysis. As a result, it was found that BUE forms around the cutting edge at low cutting speeds (5–20 m/min), and BUL, which resembles a water drop, forms on the tool rake face at cutting speeds equal to or above 40 m/min. And a thin layer of flank built-up (FBU) can form on the tool flank face as the cutting speed increases from 40 m/min to 140 m/min. The BUL/BUE formation mechanism was also confirmed. It was revealed that BUL can be considered as a protective layer, which can not only prevent the tool rake face from wear but also decrease the tool flank wear, but BUE can only prevent the crater wear; and to a certain extent, the thin layer of FBU can also work as a protecting layer on the worn tool flank face in dry cutting of SUS304. It was also revealed that the height of BUL plays a very important role in its protective effect. Meanwhile, it was found that BUL and the thin layer of FBU have no or few influences on the amplitude variation of cutting forces and on the surface roughness. These results indicated that BUL can be used to realize the self-protective tool (SPT) in cutting of difficult-to-cut material such as SUS034. In addition, the research also proved that it is necessary to take the influences of BUL, BUE, and FBU formations on tool wear into account in the tool wear model in order to achieve high-precision prediction.

Optimization of process parameters in turning of aluminum alloy using response surface methodology

The cutting forces estimation in machining process is mandatory for calculating the power requirements, cutting tool design and other accessories. The cutting force can be measured by a lathe tool dynamometer which is widely used in industrial practice. The principle of lathe tool dynamometers is based on the measurement of deflections or strain produced from the structure of dynamometer from the action of cutting force. This Paper deals with an analysis of Cutting forces, surface roughness and temperature while turning aluminium 6061 material using conventional lathe machine. In this study, three input parameters such as Depth of cut (d), feed rate (f) and Cutting Speed (s) are selected for the experimentation. Based on the selected input process parameters experiments were conducted using Central Composite Design. The response parameters such as resultant cutting forces (FC), surface roughness (Ra) and cutting temperature (TC) on selected material with variation in Depth of cut (d), feed rate (f) and Cutting Speed (s) are studied and discussed in detail.